Buy To Open Put -

: To protect an existing long stock position against downside risk. This acts as "insurance," allowing the holder to sell their shares at the strike price even if the market price crashes. Buy to Open vs Buy to Close in Options: Explained | SoFi

Traders typically buy to open a put for two primary reasons: buy to open put

A order is used to establish a new long position in a put option. This transaction gives you the right, but not the obligation, to sell an underlying asset at a specific strike price before a set expiration date. Core Objectives : To protect an existing long stock position